1. Field of the Invention
The present invention relates, generally, to testing apparatus and methods. More particularly, the invention relates to testing apparatus for gauging the ride height of a vehicle. The invention is particularly useful for gauging the ride height of a racing automobile or other high performance vehicle.
2. Background Information
The height of a vehicle from the ground or roadway is important for cars in general and is especially important in high performance racing automobiles. The handling performance of the car can be optimized by accurately measuring the ride height. Accurate ride height measurements are used to detect sagging springs, to optimize wheel alignment, to improve the suspension and traction of the car, and to verify compliance with the ride height specifications for a particular racing class of automobiles. Generally, a lower ride height is preferred over a higher ride height because it results in a lower center of gravity. In racing classes of automobiles, for example, the ride height is lowered as close as possible to the minimum ride height allowed for a particular racing class. Additionally, the front ride height is preferably lower than the rear ride height.
A lower center of gravity and wider wheel base generally provides better handling characteristics by improving the overall traction of the car. Given two cars with wheel bases of equal width and different centers of gravity, the car with the lower center of gravity rolls less and generally feels much more controlled on the road than the car with the higher center of gravity. A car with a higher center of gravity will have a larger centrifugal or roll force during cornering, which causes more actual roll effect in the car and reduces overall traction. The outside tires of a car experiencing roll effect during cornering have increased traction while the inside tires have reduced traction. However, the entire traction for all of the tires is reduced because of the roll force. Therefore, in order to maximize the overall traction, it is desirable to minimize the roll effect on a car by lowering the ride height of the car. Most racing classes impose strict limitations on the minimum ride height for this reason.
The ride height of the vehicle also contributes to the wind venturi effect produced by the airstream flowing between the bottom of the car and the road surface. The underside of the car acts as a wing to create downward force on the car and increase traction. The wind venturi effect produces a greater downward force when the bottom of the car is closer to the road surface. Furthermore, the downward force is optimized when the wing formed by the underside of the car has an optimal angle of attack, as determined by an optimized front ride height that is lower than an optimized rear ride height. The only major limitation for lowering ride height to improve handling is that, sooner or later, the bottom of the car will rub against the road surface. The bottom of the car most likely will rub the road surface either when the car is traveling through fast sections of a track where the wind venturi effect produces the highest downward force levels or when the car suspension is compressed during cornering.
The state of the art generally includes various devices and methods for measuring ride height. Ride height is often gauged using a common measuring tape. Another known device for measuring ride height is an extruded aluminum block with steps on one side. The block is slid onto the frame rail of the car to measure the ride height. These methods are believed to have significant limitations and shortcomings. The tape is not easy to align and read. Rather than providing accurate, repeatable measurements, estimating the ride height using a measuring tape inherently introduces error factors that are too great for high performance racing cars. Similarly, the accuracy of the extruded aluminum block is limited by the increment of the steps, typically 1/8 inch or 1/4 inch.
Applicants's invention provides an apparatus and method which are believed to provide improvements over existing technology.